Does Healthy Pitcher's UCL Size Matter?

San Diego teenager Brady Aiken was in line to become an extremely wealthy man, until a routine MRI apparently derailed his prospects.

He was this year's no. one pick in Major League Baseball's amateur draft, and the Houston Astros offered him a contract that included a $6.5-million signing bonus. There was just one hitch -- he would have to pass a physical exam.

An MRI scan supposedly revealed that Aiken had some abnormality with an elbow ligament, a news report said earlier this month, that had the team concerned that he was medically risky. The Astros cut their offer and Aiken remains unsigned.

The UCL stabilizes the inside of the elbow against valgus stress (stress that tends to pull the hand away from the body and open up the inside of the elbow). It protects the elbow from multiple stresses over a period of time -- such as, for a professional ballplayer, tens of thousands of hard-thrown pitches during a career, David Geier, MD, an orthopedic surgeon in Charleston, S.C., who is not involved in Aiken's case, told MedPage Today.

The reported details of Aiken's case -- which have not been confirmed by his representatives or the Astros -- do not make complete sense to orthopedic surgeon Joshua Dines, MD, of the Hospital for Special Surgery in New York City, who also has not been involved in the teen's care.

If the fear is that a small UCL could make it difficult to reconstruct the ligament if it tears later on, it is unfounded, Dines told MedPage Today.

Tommy John surgery, which reconstructs a torn UCL using a tendon from a patient's forearm, is becoming so common that it's almost a foregone conclusion that it's going to happen during a pitching career, Dines said.

But the size of the UCL does not necessarily affect the difficulty of reconstruction or its chance of success, both Dines and Geier said.

It's not the native ligament size itself that matters, Dines said. What matters is the size of the structures where the reconstruction attaches, at the humerus and ulna.

Congenitally small bony anatomy, particularly a small medial epicondyle, would be a problem.

"It's like hanging a painting on a wall," Dines said. "The painting size does not change. But if the wall is too small, it's not going to work."

On the other hand, Geier suggested that size could make a difference in the risk of injury in the first place.

There have not been any studies correlating size of UCL with likelihood of tearing, he said. This is probably because pitchers without elbow pain do not get MRIs.

But intuitively it makes sense that size could matter. "The UCL has to resist a lot of stress on that side of the elbow pitching," Geier said. "You would think that the smaller it is and the fewer collagen fibers, that potentially it's more likely to wear out over time."

And Dines said he believes that there was some genuine issue with Aiken's anatomy. He noted that the doctors who examined Aiken said there would be problems with reconstruction. "He's got doctors who agree on something, which is crazy, because that never happens at this level," Dines quipped.

"[Aiken's] camp doesn't even deny that there's an anatomical problem. They just say he's fine. They never outright said these doctors are wrong," Dines added.

Aiken is currently pitching without pain.

Although the overwhelming majority of athletes who tear a UCL are baseball players, anyone who repetitively throws overhand can suffer the injury.

Tearing of the UCL was originally described in javelin throwers in the early 1900s. Wrestlers can tear their UCLs from trauma. Tennis players and football quarterbacks occasionally injure their UCLs as well.

The ligament itself doesn't typically heal on its own, said Geier. If pain persists and function suffers after nonsurgical management, athletes will get UCL reconstruction.

But for most of society, tearing the UCL is rare except in traumatic injury. Most people don't have activities requiring the ligament's protection, said Geier.

Even with an injury, there are often no functional implications, Dines said. "For 99% of what you do in the game of life, you don't need your UCL."

Most non-athletes are treated non-operatively -- with rest from overhead activity and strengthening of forearm and shoulder muscles.

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